The invention relates to a plant-derived flocculant, a flocculant mixture, a method of flocculation, and a method for preparing the plant-derived flocculant.
With mass production and mass consumption in recent years, suspended particles discharged in water such as plant drained water keep increasing. Therefore, synthetic polymer flocculants such as polyacrylamide and copolymers thereof are generally used as flocculants for flocculate/separate microparticles dispersed in water, so as to clarify the water. However, there exist the following issues for the synthetic polymer flocculants:
[1] Even they are discharged into soil, they are accumulated rather than degraded.
[2] Their monomers themselves (acrylamide, etc.) are toxic.
[3] They are synthesized using fossil resources such as petroleum which are not renewable materials for human.
Therefore, from the perspective of environmental pollution, safety concerns and exhaustion of fossil resources, development of flocculants having good biodegradability and high safety are desired.
For natural polymer flocculants, although guar gum (seed extract of guar from Family Fabaceae), sodium alginate (extract of brown algae such as kelp, Ecklonia cava, Eisenia bicyclis, etc.), starch, gelatin, chitosan, etc. have been studied, these materials have not been widely used yet because they either are difficult to raise and cultivate, or have limited use and poor flocculability.
Moreover, according to Japanese Patent Laid-open H11-114313, a flocculant that comprises at least one of Molokheiya, dried Molokheiya, and Molokheiya extract is widely known.